The present invention relates to a clamping mechanism and more particularly to a clamping mechanism for rigidly retaining an adjustable moldboard of a motor grader in its adjusted grading position.
The moldboard of a motor grader is typically mounted for transverse adjustment relative to a blade circle to compensate for varying job conditions. Such transverse adjustment of the moldboard is conventionally achieved by laterally sliding movement of the moldboard upon its support and usually a loose sliding fit is provided between the support and the moldboard. Such loose fit is not detrimental to the operation of the motor grader in the majority of job applications since slight imperfections in the graded surface are not objectionable. However, on some finished grading operations, the blade disposition is automatically controlled relative to a preestablished reference and tolerances as small as from 1/4 to 1/8 of an inch are required. One of the problems encountered with such operation is that the loose fit permits the blade height to fluctuate within its mounting more than the allowed tolerances.
One approach to solving this problem is disclosed in the prior art wherein the blade is raised within its guide slots and locked against the upper guide slot with a hydraulic jack through a lever arrangement. However, it appears that with such an arrangement when the blade is unlocked for adjusting its lateral position, the blade would drop down against its lower slide slot due to its weight. If such adjustment is made while the motor grader is in operation the blade would gouge out a depression in the finished surface. The depression would then have to be refilled and the surface regraded.